Role of Gastric Scintigraphy in Evaluating Neuromodulatory Therapy for Refractory Gastroparesis: A Case Series and Brief Review
Poster #: 201
Session/Time: B
Author:
Virang Ketan Kumar, MD
Mentor:
Lester Johnson, MD, PhD
Research Type: Case Report
Abstract
INTRODUCTION:
Gastric neuromodulation, also referred to as gastric electrical stimulation, is a therapeutic intervention for gastric dysmotility disorders, such as refractory gastroparesis. This approach utilizes an implantable stimulator that delivers varying pulse frequencies to attune gastric contractions. Gastric emptying scintigraphy is a nuclear medicine study that assesses gastric emptying time to diagnose dysmotility. It has also been implemented in assessing response to gastric stimulation, though improved emptying can often be discordant to symptomatic relief. Thus, this study presents a case series and brief literature review to assess the utility and limitations of scintigraphy in evaluating gastric neuromodulation in refractory gastroparesis.
CASE INFORMATION:
Overall, 4 patients were included in this case series, all of whom had an established diagnosis of refractory gastroparesis with available pre- and post-implantation gastric emptying scintigraphy and reported clinical symptoms. All patients underwent concurrent pyloroplasty with gastric stimulator implantation except for patient 3. Patient 1 is a 38-year-old female presenting with nausea, vomiting, bloating, and early satiety with unsuccessful therapy involving recurrent botox injections prior to gastric electrical stimulation. Patient 2 is a 32-year-old female presenting with chronic nausea, vomiting, and bloating and did not respond to medical management with motility agents prior to stimulator implantation. Of note, Patient 2 required left colon resection with end-to-end anastomosis for chronic colonic dysmotility. Patient 3 is a 63-year-old female presenting with nausea, vomiting, dysphagia, and reflux. She has a history significant for esophageal perforation status post repair, chronic dysmotility, and unsuccessful botox therapy prior to electrical stimulator treatment for gastroparesis. Patient 4 is a 37-year-old female with a history significant for type 1 diabetes mellitus with insulin pump with chronic nausea, cyclic vomiting, and epigastric abdominal pain and unsuccessful medical management prior to stimulator implantation.
DISCUSSION/CLINICAL FINDINGS:
All patients demonstrated delayed emptying prior to intervention with >10% retention after 4 hours, and subsequent improvement to <10% retention post-implantation. Frequent symptoms included nausea, vomiting, and generalized abdominal pain. Two patients demonstrated strong clinical improvement, while one patient demonstrated only partial improvement and another was refractory despite attempted optimization of stimulation. A review of current literature highlighted that variations in institutional protocols, comorbidities, glycemic control, use of motility agents, and non-standardized symptom reporting may confound correlation with clinical response. Conversely, instances of impaired emptying with clinical improvement have been observed, theorized to possibly be related to modulation of afferent nausea pathways.
CONCLUSION:
This case review highlights the utility of scintigraphy in evaluating gastric neuromodulation, especially in cases of refractory gastroparesis. While responses can be drastically improved scintigraphically, findings may diverge from symptom outcomes for multiple reasons. Such discordance emphasizes the need for a standardized and multimodal approach to assess gastric neuromodulation and ideally incorporate scintigraphic findings with symptomatic reporting to guide therapy optimization. Future research aimed at better characterizing the discordance may be done involving prospective or retrospective studies, while also assessing varied standardization protocols for treatment response reporting.
Gastric neuromodulation, also referred to as gastric electrical stimulation, is a therapeutic intervention for gastric dysmotility disorders, such as refractory gastroparesis. This approach utilizes an implantable stimulator that delivers varying pulse frequencies to attune gastric contractions. Gastric emptying scintigraphy is a nuclear medicine study that assesses gastric emptying time to diagnose dysmotility. It has also been implemented in assessing response to gastric stimulation, though improved emptying can often be discordant to symptomatic relief. Thus, this study presents a case series and brief literature review to assess the utility and limitations of scintigraphy in evaluating gastric neuromodulation in refractory gastroparesis.
CASE INFORMATION:
Overall, 4 patients were included in this case series, all of whom had an established diagnosis of refractory gastroparesis with available pre- and post-implantation gastric emptying scintigraphy and reported clinical symptoms. All patients underwent concurrent pyloroplasty with gastric stimulator implantation except for patient 3. Patient 1 is a 38-year-old female presenting with nausea, vomiting, bloating, and early satiety with unsuccessful therapy involving recurrent botox injections prior to gastric electrical stimulation. Patient 2 is a 32-year-old female presenting with chronic nausea, vomiting, and bloating and did not respond to medical management with motility agents prior to stimulator implantation. Of note, Patient 2 required left colon resection with end-to-end anastomosis for chronic colonic dysmotility. Patient 3 is a 63-year-old female presenting with nausea, vomiting, dysphagia, and reflux. She has a history significant for esophageal perforation status post repair, chronic dysmotility, and unsuccessful botox therapy prior to electrical stimulator treatment for gastroparesis. Patient 4 is a 37-year-old female with a history significant for type 1 diabetes mellitus with insulin pump with chronic nausea, cyclic vomiting, and epigastric abdominal pain and unsuccessful medical management prior to stimulator implantation.
DISCUSSION/CLINICAL FINDINGS:
All patients demonstrated delayed emptying prior to intervention with >10% retention after 4 hours, and subsequent improvement to <10% retention post-implantation. Frequent symptoms included nausea, vomiting, and generalized abdominal pain. Two patients demonstrated strong clinical improvement, while one patient demonstrated only partial improvement and another was refractory despite attempted optimization of stimulation. A review of current literature highlighted that variations in institutional protocols, comorbidities, glycemic control, use of motility agents, and non-standardized symptom reporting may confound correlation with clinical response. Conversely, instances of impaired emptying with clinical improvement have been observed, theorized to possibly be related to modulation of afferent nausea pathways.
CONCLUSION:
This case review highlights the utility of scintigraphy in evaluating gastric neuromodulation, especially in cases of refractory gastroparesis. While responses can be drastically improved scintigraphically, findings may diverge from symptom outcomes for multiple reasons. Such discordance emphasizes the need for a standardized and multimodal approach to assess gastric neuromodulation and ideally incorporate scintigraphic findings with symptomatic reporting to guide therapy optimization. Future research aimed at better characterizing the discordance may be done involving prospective or retrospective studies, while also assessing varied standardization protocols for treatment response reporting.